https://github.com/smallkirby/ymir

Ymir: The Type-1 Hypervisor.
https://github.com/smallkirby/ymir

hypervisor zig

Last synced: 24 days ago
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Ymir: The Type-1 Hypervisor.

• Host: GitHub
• URL: https://github.com/smallkirby/ymir
• Owner: smallkirby
• License: mit
• Created: 2024-08-10T11:35:16.000Z (over 1 year ago)
• Default Branch: master
• Last Pushed: 2025-06-18T10:25:44.000Z (8 months ago)
• Last Synced: 2025-11-05T18:30:41.592Z (3 months ago)
• Topics: hypervisor, zig
• Language: Zig
• Homepage: https://hv.smallkirby.com
• Size: 813 KB
• Stars: 47
• Watchers: 1
• Forks: 3
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE
  • Codeowners: .github/CODEOWNERS

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README

          
# Ymir: The Type-1 Hypervisor

![Zig](https://shields.io/badge/Zig-v0%2E14%2E0-blue?logo=zig&color=F7A41D&style=for-the-badge)

![Lint](https://github.com/smallkirby/ymir/actions/workflows/lint.yml/badge.svg)

![Test](https://github.com/smallkirby/ymir/actions/workflows/test.yml/badge.svg)

![Boot Linux](https://img.shields.io/travis/com/smallkirby/ymir?style=flat&logo=travis&label=Boot%20Linux)

Ymir is an Intel VT-x based baremetal hypervisor written in Zig.

It is minimalistic but can boot latest Linux kernel (v6.9).

![Ymir Logo](assets/ymir.png)

## Features

- Supports Intel x64 architecture.

- Can boot latest Linux kernel with initramfs.

- Uses EPT (Extended Page Tables) for memory virtualization.

- Super thin (passthrough) and minimalistic hypervisor.

- No dependencty. Everything is written from scratch in Zig.

## Limitations / Future Work

- No support of SMP.

- No support of APIC and other fundamental features.

- Can boot only Linux kernel with [x86 boot protocol](https://www.kernel.org/doc/html/v6.1/x86/boot.html).

- Can host only one VM at a time.

- And many more...

## Requirements

Install `ovmf` package to run UEFI firmware on QEMU:

```sh

sudo apt install ovmf

```

## Development

```sh

zig build install-samples

zig build run -Dlog_level=info -Doptimize=ReleaseFast

```

If you want to use your own kernel image and initramfs,

you can put your kernel image (`bzImage`) and initramfs (`initramfs.cpio`) to `/zig-out/img`.

It is tested that Ymir can boot Linux kernel v6.9 that is compiled with `defconfig` of x86-64.